export function createStore(reducer){
    let currentState = {}
    let currentListeners = []

    function getState(){
        return currentState
    }
    function subscribe(listener){
        currentListeners.push(listener)
    }
    function dispatch(action){
        currentState = reducer(currentState, action)
        currentListeners.forEach(v => v())
        return action
    }
    dispatch({type: '@imooc/jfid/redux'})
    return {getState, subscribe, dispatch}
}